Method of manufacturing solutions of caoutchouc.



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'eto-Qhavebeen employed extensively commercially for obtainin caoutchouc I unirn snares Parana heron EMIL FISCHER, OF SCHONEBERG, NEAR BERLIN, GERMANY, ASSIGNOR TO SIEMENS d: HALSKILA. G., OF BERLIN, GERMAN Y, A CORPORATION OF GERMANY.

IYIETHOD OF MANUFACTURING SOLUTIONS OF GAOU'ICHOUC.

, Specification of Letters Patent.

Patented Jan. 26, 1909.

Application filed January 16, 1908. Serial No. 411,137.

To all whom it may concern:

Be it l-mown that l, EMU. Fisensn, a subject of the German Emperor, and residing at Coburgerstrasse 17, Schr'ineberg, near Berlin, Germany, haveinvented a new and useful Improved Method of Manufmturing Solu tions of ()aoutchouc, of which the following is a specification.

-The present invention relates to a method of manufacturing solutions of caoutchouc.

Hitherto numerous solvents have been pro osed for raw iein, such as, for example, carbon disulfid, benzene, chloroform, carbon tetrachlorid,

solutions.

- i\,1any.defeets however are attached to all those solvents, such either easy inflame specific weight or anesthetizing action; *urther, it has been found that for the urpose of obtaining concentrated ca'outo 1011C solutions the dissolving Inability or too higlh power of most of the above mentioned solvents is not sufficient, or the caoutchouc is only soakcd or steeped in the liquid instead of dissolved. w

A solvent which does not possess the last mentioned defects has been found in s mmetrical dichlorethyleno ClHCzCHCl.

his substance was proposed quite enerally as a valuable solvent in the British Patent Specification 19,568 of 1904, but was never recognized as an exceptionally important solvent of eaoutehouc Y Now according to my investigations it has been found that, with regard to' its solvent power, dichlorethylene considerably excels even chloroform and ethan tetrachlorid whi ch were formerly known as the best dissolving materials, as the following numbers move. 10 g. of each of two kinds of raw caoutchouc stood 24 hours at an ordinarytemperature with 250 c. ems. solvent with frequent stirring and the following quantities of caoutchouc were dlssolvedz caoutchouc, but only few Para raw Borneo raw Caouzchouc. l Caoutchouc.

Dichlorethylene (spec. rgt. 1.2694)...

i 99. i 95.9% Ethan tetrachlorid (spec. wgt. 1.588). 75. t% i 46. 4% Chloroform (spec. \vgt. 1.494 7 1. 9% 1 5c. 8%

The new solvent dichlorethylene, a translucent liquid boiling at C., possesses the following additional advantages as compared with liquids used hithertovin the art or mantfacturing caoutchote solutions:

1. At the ordinary temperature of a room it has a very considerably greater power of dissolving raw caontcl'ioue. 'l he solutions obtained with it, including even those most concentrated, are completely homogeneous and free from ltmps.

2. Greater liquidity in consequence of the low boiling point.

3. It is incombrstible, and does not generate explosive mixtures of gases or vapors When heated.

4:. It has a lower specific weight than those known solvents \rhlch are nearest to dichlorcthylcnc with regard to solvent power.

Example. F or reparing an approx. 3% Para raw caoutc 101.0 soletion, 2.5 liters dichlorethylene are added to 100 g. comminuted raw cam tchoitc, and the niixtrre is left standing with frequent stirring, with-- 'WOLDEMAR HAUPT, HENRY HAsPER. 

